Real-time fluoroscopic imaging systems in which an x-ray emitter is in a fixed relationship relative to an x-ray detector are in widespread use. The emitter and detector are typically mounted on opposing ends of a one-piece support assembly such as a C-shaped arm. A variation known as a mini-C-arm is particularly useful for imaging extremities. Various improvements have been made since such imaging systems were initially developed. For example, the x-ray detector may include a digital x-ray flat-panel detector (FPD) with an complementary metal-oxide-semiconductor (“CMOS”) device. FPDs have better dynamic range and detection quantum efficiency (DQE) than previous detectors.
It is recognized that it is desirable to be able to reposition the support assembly to which the emitter and detector are mounted. For example, it may be desirable to obtain a second, orthogonal view through the target when repairing a fracture or for implant placement. This can be accomplished by either repositioning the support assembly or, alternatively, using two imaging systems at right angles to one another. The support assembly may be supported by a mechanism that enables rotation about an axis in order to help orient the emitter and detector relative to the target. The mechanism may be coupled to a cart or ceiling mount. Regardless of the type of assembly used to fix the position of the emitter relative to the detector, maintaining the relative positioning of the emitter relative to the detector while enabling repositioning of the assembly facilitates ease of use.